Alternatively, the pour-on approach seems so easy it might be underestimated. There are several pour-on products effective for fly control, de-worming, delousing and controlling internal parasites in cattle – especially when they are used properly.
According to Bob Sager, DVM, Ph.D., “Pour-on products are often underdosed – and thus less effective.” When a medicine isn’t dosed properly, it leads to resistance in the parasite population.
Lew Strickland, veterinary extension at the University of Tennessee, says, “Resistance is a producer’s biggest problem.” This may come from inadequate dosing or parasite cycles. Both Strickland and Sager agree one of the biggest tips is the simplest: Read the label.
Reading the label seems like common sense, but these labels will detail everything from adequate distance from bodies of water, to cautions in case of human contact, to storage directions, to dosing instructions. Strickland says, “Use pour-ons when the weather is amendable to using them, such as in dry conditions.
The hide needs to be dry.” The label will help you determine the drying time needed for efficacy.
Sager recommends producers first verify the need for pour-on products. “Pour-on products treat external and internal parasites. Often product is used when it isn’t needed or at the wrong time of year. The best thing to do is a fecal analysis. A fecal analysis will tell you the type of parasite you are dealing with, and thus we can find the appropriate chemical to combat it.”
If a product is needed, Strickland suggests (in the case of external parasites) staying with one class of pour-ons for one to two years. “For instance, if you need pyrethroid, then use it in your pour-ons and also in your rubs or tags should you need them. Don’t mix classes of chemicals in the same year.”
Once you’ve decided to use a pour-on product, Strickland says, “Start at the withers and go down the back 18 to 24 inches, making sure you go down the back with the product.” Sager shares, “Many producers just squirt the product in one place, and you can see it dripping off their hide as they walk out of the chute. That animal was just underdosed and subject to resistance.”
Pour-on products have been on the market for about three decades, giving them plenty of time to build resistance. “Any time you kill off parasites, all you have left are the resistant parasites. Then they reproduce, and we end up with a population of resistant parasites,” states Strickland.
The best ways to eliminate this problem in your herd is to read and follow all label instructions and also treat your animals at opportune times. Once you’ve treated for parasites, wait no longer than one week before moving them to a clean pasture.
This avoids re-contamination of parasites shed through the feces. Sager adds, “Rotational grazing and leaving around 4 inches of grass is helpful in reducing parasite problems. In other words, don’t graze to the bare stubs. Then your need for pour-ons is reduced.”
Also, many producers forgo treating bulls, but if you use pour-ons with cows, be sure to treat bulls too or you may see re-contamination.
Both experts encourage brand-name product in most situations, even though the price is considerably higher. “Generics tend to be used more often, and increased use generates resistance. In addition, brand-name products will back their product, especially if you have the lot number off the label,” says Strickland.
“Don’t just buy product thinking you need it,” says Sager. “Consulting with an animal health expert who knows your herd and the life cycle of parasites will give you the best benefits. Folks may use a pour-on in August but see lice during calving. Waiting until November may give you the best benefits and reduce rubbing on your fences. Knowing the life cycles will help you determine that.”
Sager and Strickland say pour-on products have increased in quality over the years and, when used appropriately, will be effective. Proper use will not only be better for the cattle but also for your pocket book. It all comes down to “being cautious and using products exactly as stated on the label,” says Strickland. 
PHOTO: Reading the label before using any pour-on product is a producer’s best defense. Photo by Marci Whitehurst.
Marci Whitehurst is a freelance writer based in Montana.
